Pressure sensitive manifold sheet



2,711,375 7 7 V PRESSURE SENSITIVE MANIFOLD SHEET Robert W. Saudberg, Dayton, Ohio, assignor to 'ihe. National Cash Register Company, Dayton, Ohio, 21

corporation of Maryland No Drawing. Application February 19, 1954,

Serial No. 411,580 r 2 Claims. (Cl. 117-36) This invention relates to a record, material transfer sheet, useful in duplicating and manifolding operations,

and more particularly relates to such a sheet in which the transfer coating has, therein, material which prevents smudging during ordinary handling of the paper but which in no way interferes with the transfer characteristics of the sheet.

case with ordinary carbon paper. Thetransfersheet pro 7 Y i vided by thisinvention has the cellulose fiberingredients' has been made and of which this is ajcontinuation in, part, is disclosed: in United States-Letters.PatentjNoe This is a continuation in part of myapplication for United States Letters Patent Serial No. 243,583, filed August 24, 1951, now abandoned. In the mentioned application, of which this is a continuation in part, the invention was described with reference to a transfer coating which consisted of a hydrophilic colloid film having dispersed therethrough a profuse number of microscopic droplets of an oily marking fluid. This transfer film was derived from an oil-in-Water emulsion. The outer phase of the emulsion was the film-forming colloid material, dispersed in water. The invention described in that apnumberjof individual capsulesof-hydrophilic colloid material, of. miscroscopic sizegeach capsule containing one.

plication provided for the inclusion in the emulsion of .a

certain amount of microscopic cellulose fibers. Because of the nature of the emulsion, the amount of cellulose fibers which could be used was limited due to the fact that a 7 any increase of over 70% of fiber, as comparedto the weight of the dried colloid material, would be deleterious to the emulsion, so that proper coating could not be made therewith. Since the filing ofsaid application, there has been developed a coating composition which may be coated on paper to produce a manifold sheet, the coating 7 being of hydrophilic colloid material containing oily droplets of marking fluid, but each droplet is encased in its own capsule of the colloid material, and it is derived, not from an emulsion, but from a process of coacervation, as will be explained. Because of this capsule formation on a microscopicscale, as little or as much cellulose fiber may be used to make the coating to be applied with the paper as is desired, and, hence, the limits of added fiber material set out in the application to which reference has been made are no longer important.

The invention will be described with reference both to the embodiment found in said earlier-filed application and to the embodiment in which encapsulated droplets of printing fluid from the major portion of the coating composition. 7 h

In both instances, the transfer filmis rupturable by marking pressures, so as torelease the oily marking fluid from the hydrophilic colloid, whether in a continuous film form or in the microscopic capsule form. In a'transin the film to prevent such smudging.

The continuous-film type for transfer recordmaterial, which is the embodiment disclosed'intheprevious applicationfor United States Letters Patent, to which reference 2,374,862, which issued on the applicatio n o f BarretLK. Green; and in United States'Letter'sPatent Nail-548,366,

which issuedon thev applicationbf Barrett K. Green and Robert' 'W. Sandber'g. In the 'firsttmentioned patent, thefront surface of the record material sheetisleft uncoated,"- I and the oily material in the transfer filni' onthe rearsur-* I face'contains eithercoloring'matterinthe coloredstate, r or colorless color-reactant material, for use on" sensitized urecordmaterial, whichcau'ses the'app'earanceof color in f the ,oil transferred thereto by reasonof a 'colorreaction.

In the last mentioned patent, the-frontsurface ofthesheetQ of record materialiis coated with: a sensitizing material,

which causes color-"in a. colorless colorireactantapplied thereto, and the rear surface hasia coating containingthe oil droplets of the colorless color reactant, said record sheet'being useful-as one of the middle sheets of a stack and acting in the capacity of both a transfer'sheetand'a I "receivingslieet. a. W

In the second, andpreferred, embodimentofthe-inven- I tion, as hasbeen-said, the transfer coating consists offa' or more. oil droplets containing the marking ingredient;

This-type oftmanifold sheet is described in'anapplication for United States Letters Patent, Serial No. 365,198, filed June 30, 1953;by BarrettK 'gGreen and LowellSchleichera The cellulose fibers'iare preferably alpha-cellulose, and

those used in the'continuous typeof'film'derived froman emulsion should be not more than approximately 35 microns in length, soas not to interferewith the er nulsionf y structure. In the capsular type ofcoating, with which there is' no, danger-of interfering with the emulsion, the Z fibers may be up to 350 Iriicronsin length or more. a

Whereas in a continuous type of tran'sferfihn there may be used 7% to 70% of fibers, by weight, based on the:

dried colloid material without the'liquid .inclusions, the

,cellulose 'fibers may be used with the capsule type of,

transfer coating ini'any qua'ntity desired, as long as'the coating holds together, on the paper. 1

Therefore, itiis an objectof thisinvention to provide a record sheet having thereon a transfer coating which 1 includes fluid droplets-of marking fluidprotectedfrom escape *by film-forming hydrophilic "colloid material which is rupturable by marking or printing pressures to release the'oil; and which hydrophilic colloid material hasincorporated therein cellulosetfibers of microscopic} si ze, which cause the transfer film to be resistant to destruction by rough handling, so'as not tojprematurely' release theoily marking fluid.

With this and'incidentalobjects in view, the invention includes certain novel" features, the preferred and other embodiments'of which are-hereinafter described in this specification.

for sheet having a film of the novel coating, as pressure is i applied by a writing or printing instrument, the 'hydrophilic material is ruptured at the points of pressure, allow- 7 ing the fluid to be transferred to the undersheet.

In collated forms consisting of an oversheet, jtheunder side of which has thereon the novel transfer film in one or the other of the forms which will be described, and'an undersheet to receive the transfer of material, thecontact of the transfer film with the undersheet, if long continued under pressure, will result in smudging, as would be the i As has been'said, the continueus-film type of transfer coating is an emulsion made from a sol of hydrophilic V g colloid material'which' forms the external phase, and an.

oily marking fluid whichforms the internalphase; The cellulose fibers can beadded eitheifto Ltheinternal phase material, to the external phasematerial, or to both ina; V terials before they are emulsified together, "or into the emulsion after the first-blending of the two pliases.:.j'll1e' L emulsion isjnoreeasilyfmade by adding the cellulose, fibers to the internal phasematerial before it is blended" I wit htthe external phaseimaterial, because of the 'c ontact V f 2,711,375 Patented June a1, 55

l) of said cellulose fibers with the oily internal phase mate rial, and the method of preparing the coating will be described with that in mind.

In the continuous-film type of coating, the selected marking material is a colorless color-reactant compound, which is dissolved in a chlorinated diphenyl of approximately 48% chlorine content, and the process of making it will largely follow that disclosed in United States Letters Patent No. 2,548,366, of Barrett K. Green and Robert W. Sandberg, the novelty over such method as disclosed in said patent being the use of cellulose fibers.

The external phase material is made by incorporating one part, by weight, of animal gelatin, having an isoelectric point of pH 8 and a jelly strength of 275 grams, as measured by the Bloom gelometer, in three parts, by weight, of water, heated to 150 degrees Fahrenheit, to form a sol.

The internal phase is made by dissolving 1%. parts, by weight, of crystal violet lactone, and 1 /2 parts, by weigl t, ofbenzoyl leuco methylene blue in 97 parts, by weight, of chlorinated diphenyl, as specified. Alpha cellulose fiber, as specified, in an amount whi h will be equivalent to 4%, by weight, of the finished emulsion, is mixed into the solution which is to form the internal phase. Into four parts, by weight, of the external phase is blended three parts, by weight, of the oily internal. phase material plus the added cellulose fiber. These materials are then emulsified by stirring for the required period.

The finished emulsion is applied While still hot, or reheated if it has been allowed to cool, to paper, and dried. The coating is applied in such an amount that, when dried, the coating will be of the order of .001 of an inch in thickness. As has been said, the preferred average drop size is of the order of 2 /2 to 3 /2 microns, the presence of the cellulose fiber making the drop size more uniform than would be the case if the cellulose fibers were not usd. in emulsions where the cellulose fiber is not used, such might end with the spread of the internal drop size between 1 and 5 microns. As mentioned, the alpha cellulose is preferred, and the fiber length should be of the order of five to ten times the diameter of the average drop of the internal phase, although that ratio is not critical. This emulsification takes about thirty minutes, by stirring in an open receptacle.

The specified crystal violet lactone is a colorless, or white, crystalline compound, which assumes a dark blue color on contact with acid-like clay, such as attapulgite, with which paper may be sensitized, such sensitized paper also being disclosed in the United States Patent No. 2,543,366, just mentioned. The molecular formula of crystal violet lactone is 3,3 bis (p-dimethylaminophenyl)- 6 dimethylamino phthalide, and the crystal violet lactone may be made by the process disclosed in United States Letters Patent Re. 23,024, which issued on the application of Clyde S. Adams.

The benzoyl leuco methylene blue has the following structure:

and may be purchased commercially.

The emulsion coating may be air-dried at normal temperature or by a hot-air blast.

in this embodiment of the invention, the fibers of cellulose first come into contact with the oil internal phase and then become incorporated in the external phase. If desired, all or part of the cellulose fibers are put into what a. is to become the external phase before the intended external phase and the intended internal phase are blended together. This results in the very satisfactory smudgeproof record material, and the required time of emulsification is reduced. If it is so desired, the cellulose fibers may be beaten into the emulsion ingredients while in the emulsification stage, and they may be incorporated therein at any time up to and including the final stirring. Of course, the latter event, the fibers play no part in reducing the required emulsification time, and the finished rec rd material made therefrom is not quite as good as that made from process.

Among the very many useful color-reactant compounds which may be used in place of the crystal violet lactone and the benzoyl lecuo methylene blue are the following:

3,3 bis (p-dimethylaminophenyl) phthalide 3,3 bis (p-dimethylaminophenyl)-4,5,6,7 tetrachloro phthalide 3,3 bis (p-diethylarninophenyl) 6 dirnethylamino phthalide 2,4 bis [p-(p-dirnethylaminophenylazo) anilinol-6 hydroxy sym. triazine Already colored compounds which may be used instead of a color-reactant compound are Sudan Ill; carbon black, which may be mixed with oil; Sudan IV; and oilsoluble nigrosine.

The gelatin of the external phase may be replaced by polyvinyl alcohol, if desired.

Other oils that may be used in place of the chlorinated diphenyl are paraflin oil, naphthenic oil, castor oil, neatsfoot oil, lard oil, olive oil, tributyl phosphate, and ethylphthalyl-ethyl-glycollate.

The preferred embodiment, in which the transfer coating consists of microscopic capsules containing the marking oil mixed with the cellulose fiber In the preferred embodiment of the invention, the capsules containing the printing fluid are made first, and

then the cellulose fibers are added with a binder, so that they are not within the colloid itself but are interlaced in and around the colloid capsules.

First will be described the method of making the capsules, in accordance with the application for United States Letters Patent Serial No. 365,198, of Barrett K. Green and Lowell Schleicher, filed June 30, 1953, before mentioned.

The encapsulating material, which encloses the oil droplets, is a complex of gelled hydrophilic colloid materials. The printing fluid of the preferred type is the crystal violet lactone mentioned in connection with the first embodiment specified above, dissolved in oil, which produces dark blue marks when coming into contact with record material sensitized with clay-like material such as attapulgite, or zeolite material such as sodium aluminum silicate material.

In forming the capsules from a complex of gelatin and gum arabic, 20 grams of gum arabic is dissolved in 160 grams of water, and into that is emulsified 80 grams of trichlordiphenyl containing 3% to 6%, by weight, of the color-reactant material crystal violet lactone, and the additive material benzoyl leuco methylene blue, before mentioned, in equal amounts. The emulsification is carried on until the drop size of the oil is from 2 to 5 microns. grams of water and mixed with the emulsion. This emulsion is then diluted by adding Water uniformly and slowly, with agitation, until coacervation occurs, the complex gum arabic-gelatin colloid material forming around the droplets of the oil. These colloid-surrounded droplets make aggregates of from several microns in diameter up to microns in diameter, depending upon the rate and extent of dilution. The added water should amount to about 500 to 550 grams. Up to this time, all

the emulsion of the first-described Next, 20 grams of gelatin isdissolved in 160.

the ingredients are kept at approximately 50 degrees centigrade, which is above the gel point of the ingredients. Now that the colloid material has deposited around the oil droplets, forming particles, the colloid.

material is caused to gel by pouring in a quantity of col-l water; for instance, water at zero' degrees centigrade. The mass is agitated and then let stand for one hour at not over 25 degrees centigrade. At this point, the total weight of all the ingredients should be about 3960 grams. At this point, the pH is adjusted to between 9 and 7, such adjustment being made with sodium hydroxide, and

the material is left for thirty minutes or more in this The capsules are then hardened by pouring in state. about 20 grams of a solution of formaldehyde in water,

of about 37% formaldehyde content, and the materials solids in the paper-coating composition would consist of 100 grams of the capsules, with the included oil, taken on a dry basis-that is to say, without the water-40 grams of cellulose fiber, and grams of paper-coating starch. The amount of fiber is not critical, and as lit-' tle or as much as desired may be used.

The coating composition containing the cellulose fibe is coated on paper by' any of the well-known paper-- coating'means, as by brushing or roller-coating, and

dried. As before said, the fibers may be of any size desired, fiber lengths as long as 350 microns not being appre ciably noticeable in the coating. 7

While the form of the invention shownand described herein is admirably adapted to'fulfill the objects pri- In a typical example of paper-coating composition, the

marily stated, it is tobeunderstood that it is not in-- tended to confine the invention to the one form or, em-

bodiment disclosed herein, for it issusceptible of em bodiment in various other forms.

What is claimed is:

'1. A manifold sheet having a coating thereon of pressure-rupturable hydrophilic colloid material enclosing microscopic discrete liquid inclusions of an oily marking substance and the coating containing microscopic fibers of cellulose isolated from the'liquidiinclusions, and said fibers being present in an amount not to exceed by weight based. on the dried colloid material without the liquid inclusions'an'd not exceeding 35 microns in length. j a

2. A manifold sheet having thereon a coatfnglof pressure-rupturable microscopic capsules of hydrophilic colloid material, each capsule containing an oily marks ing fluid and the coating containing interlaced around the capsules microscopic fibers of cellulose.

References Cited in the file of this patent UNITED:'STATES PATENTS 2,655,453 Sandberg 0 t.-13,1 s 

1. A MANIFOLD SHEET HAVING A COATING THEREON OF PRESSURE-RUPTURABLE HYDROPHILLIC COLLOID MATERIAL ENCLOSING MICROSCOPIC DISCRETE LIQUID INCLUSION OF ANY OILY MARKING SUBSTANCES AND THE COATING CONTAINING MOCROSCOPIC FIBERS OF CELLULOSE ISOLATED FROM THE LIQUID INCLUSIONS, AND SAID FIBERS BEING PRESENT IN ANY AMOUNT NOT EXCEES 70% BY WEIGHT BASED ON THE DIRED COLLOID MATERIAL WITHOUT THE LIQUID INCLUSION AND NOT EXCEEDING 35 MICRONS IN LENGTH. 